Burosumab, sold under the brand name Crysvita, is a human monoclonal antibody medication approved 2018 for the treatment of

X-linked hypophosphatemia X-linked hypophosphatemia (XLH) is an X-linked dominant form of rickets (or osteomalacia) that differs from most cases of dietary deficiency rickets in that vitamin D supplementation does not cure it. It can cause bone deformity including short s ...

and tumor-induced osteomalacia.

Medical uses

In the European Union and the United States, burosumab is indicated for the treatment of adults and children ages one year and older with

(XLH), a rare, inherited form of rickets. caused by overproduction of a hormone called

FGF23 Fibroblast growth factor 23 (FGF23) is a protein and member of the fibroblast growth factor (FGF) family which participates in the regulation of phosphate in plasma and vitamin D metabolism. In humans it is encoded by the gene. FGF23 decreases rea ...

(fibroblast growth factor 23) in bone cells. FGF23 is responsible for blocking phosphate re-absorption in the kidney and the suppression of the vitamin D dependent phosphate absorption in the intestine. Due to the excess activity of FGF23, phosphate levels in the blood are abnormally low (

hypophosphatemia Hypophosphatemia is an electrolyte disorder in which there is a low level of phosphate in the blood. Symptoms may include weakness, trouble breathing, and loss of appetite. Complications may include seizures, coma, rhabdomyolysis, or softening ...

), which affects the constitution of bone. Thus, burosumab is designed to bind to the FGF23 receptor and inhibit the excess activity of the FGF23 hormone within the body. In the United States, burosumab is also approved to treat people age two and older with tumor-induced

osteomalacia Osteomalacia is a disease characterized by the softening of the bones caused by impaired bone metabolism primarily due to inadequate levels of available phosphate, calcium, and vitamin D, or because of resorption of calcium. The impairment of bon ...

(TIO), a rare disease which is characterized by the development of tumors causing weakened and softened bones. The tumors associated with TIO release fibroblast growth factor 23 (FGF23) which lowers phosphate levels.

Legal status

It was approved for use in the European Union in February 2018 to treat children one year of age and older and adolescents with growing skeletons who have X-linked hypophosphataemia with radiographic evidence of bone disease . In April 2018, the U.S.

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...

(FDA) approved burosumab for its intended purpose in patients aged one year and older. The FDA approval fell under both the

breakthrough therapy Breakthrough therapy is a United States Food and Drug Administration designation that expedites drug development that was created by Congress under Section 902 of the 9 July 2012 Food and Drug Administration Safety and Innovation Act. The FDA's "br ...

and orphan drug designations. The FDA considered it to be a

first-in-class medication A first-in-class medication is a pharmaceutical that uses a "new and unique mechanism of action" to treat a particular medical condition. While the Food and Drug Administration's Center for Drug Evaluation and Research tracks first-in-class medicat ...

. In 2018, the

National Institute for Health and Care Excellence The National Institute for Health and Care Excellence (NICE) is an executive non-departmental public body of the Department of Health and Social Care in England that publishes guidelines in four areas: * the use of health technologies withi ...

in England and Wales raised concerns regarding the incremental cost-effectiveness of the new treatment but as of 2019 the drug was available through a simple discount scheme.

History

This drug was developed by Ultragenyx and is in a collaborative license agreement with Kyowa Hakko Kirin.

References

External links

* {{Portal bar , Medicine Breakthrough therapy Monoclonal antibodies Orphan drugs Therapeutic antibodies